Steel casting with hardened portions and process of making same.



No. 728,217. PATENTED MAY 19,1903.

H. W. FALK. STEEL CASTING WITH HARDENED PORTIONS AND PROCESS OF MAKING SAME. APPLICATION FILED FEB. 1a, 1902.

no MODEL.

UNITED STATES Patented May 19, 1903.

PATENT OFFICE.

HERMAN W. FALK, OF MILWAUKEE, WISCONSIN, ASSIGNOR TO THE FALK COMPANY, OF MILWAUKEE, WISCONSIN, A CORPORATION or WISCONSIN.

STEEL CASTING WITH HARDENED PORTIONS AND PROCESS OF MAKING SAME.

SPECIFICATION forming part of Letters Patent N 0. 728,217, dated May 19, 1903.

Application filed February 13, 1902.

To aZZ whom it may concern: 7

Be it known that I, HERMAN W. FALK, a citizen of the United States, residing at. Milwaukee, in the county of Milwaukee and State of Wisconsin, have invented certain new and useful Improvements in Steel Castings with Hardened Portions and Processes of Making Same, of which the following is a-specification, reference being had to the accompanying drawings, forming a part thereof.

This invention relates to a method of producing steel castings whereby any partor portion of the casting which it is desired to have harder than the remainder can be rendered so.

The primary object of the invention is to provide a method whereby the desired parts or portions of steel castings may be rendered harder than the remainder irrespective as to whether said portions are at or near the surface of the castings, at the center, or at any portion of the same.

For carrying out the process and producing the improved casting in the broadest purview of the invention I support a hardening substance within the cavity of the mold in which the casting is to be made in such manner that the molten steel may pass entirely around the hardening substance, or partially therearound, or between the hardening substance and the walls of the mold, whereby the hardeningsubstanceis fusedbyandincorporated in the molten steel and the desired portions of the casting are made harder than the other portions.

Although the process is applicable to the production of a great variety of articles, for the purpose of illustration it will be particularly described and explained as applied to the production of railway-frogs and brakeshoes.

In the accompanying drawings, Figure 1 is a plan view of a steel railway-frog cast in one piece, with hardened points and parts adjacent thereto indicated by stipple shading. Fig. 2 is a crosssection of the frog on the line 2 2, Fig. 1, the hardened portion of the casting beingindicated by double hatching. Fig. 3 is a cross-section, on the line 3 3, Fig. 4, of

Serial No. 93,857. (No specimens.)

a mold as prepared according to my invention for casting the frog shown in Figs. 1- and 2. Fig. 4 is a plan view of a mold for casting the frog prepared in accordance with my in? vention. Fig. 5 is a view of a brake-shoe cast in accordance with the invention, and Fig. 6 is a longitudinal section of a mold arranged in accordance with the invention for casting the shoe shown in Fig. 5.

In carrying out my invention a mold is built up in the usual way of sand, as shown in Figs. 3, 4, and6, varying in shape and details according to the shape and nature of the article to be cast. After the mold has been formed the parts are'separated, and some suitable hardening substance, such as manganese, which has the property when incorporated with steel of rendering the steel hard and tough, is supported in the cavity of the mold in position to be fused by the molten steel when it is poured into the mold and diffused through and incorporated with that part of the casting which is to be hardened, the said manganese or other hardening substance beingso supported in the cavity that the molten steel may pass either ontirely around said hardening substance, or partially therearound, or between the hardening substance and the walls of the mold.

The manganese, supported as indicated, is preferably confined or incased. To accomplish this, the manganese is pulverized or broken sufficiently to be conveniently inserted and contained in a tube or case of any convenient shape and material that will be readily fused by the molten steel when it is poured into the mold. Ordinarily in the use of manganese for hardening purposes the gases escaping from the manganese produce asputtering, which results in a rough exterior surface to the casting. By confining the manganese in the manner indicated, however,-

this sputtering is prevented, as the molten steel is compelled to melt the surrounding confining-casing before the manganese are reached and fully released, and hence said manganese is fused gradually by the molten steel, and the sputtering and consequent roughening of the metal which is occasioned by the too rapid fusing of manganese is thereby prevented. I have also found by experience that the surrounding confining-casing may advisably be of aluminium, as this metal has been found in practice to possessa quieting and solidifying effect on the manganese and which assists in preventing the objectionable sputtering referred to.

For casting a railway-frog A with hardened points (L a and heads I) 1) adjacent to the intersection of the grooves c c for the flanges of the wheels, as shown in Figs. 1 and 2, an ordinary green-sand mold D D is made,as shown in Figs. 3 and 4. Pulverized or broken manganese or other suitable material which incorporated with the steel will render it hard and tough is preferably inclosed-in tubes e e, advisably of aluminium, or receptacles of any desired shape or material that will be readily fused by and incorporated with the molten steel. These tubes are then secured by any suitable means, as by pinsff, nails, &c., in the cavity of the mold in position to be diffused through and incorporated with that part of the casting which it is desired to harden, the position of the tube being such that the molten steel may flow entirely around it, although the tube may be so positioned that the molten steel will only flow partly around it or between it and the walls of the mold. For casting a frog like that shown in Figs. 1 and 2 the tubes e e, containing the manganese or other hardening substance,may be arranged, as shown in Figs. 3 and 4, lengthwise of the mold and parallel with the adjacent walls of the mold by which the hardened portion of the casting is to be formed. To hold the manganese or other hardening material in the tubes if the latter are made of aluminium or other soft or malleable metal, the ends of the tubes may be conveniently closed by flattening or drawing them together, as shown in Fig. 4. For casting a brake-shoe like that shown in Fig. 5 or similar articles in which it may be desirable to have a working face with hardened parts alternating with soft tenacious parts, short tubes 6 with the manganese or other hardening substance may be stuck into the sand mold, as shown in Fig. 6, perpendicular to the wall which is to form the surface of the casting having hardened parts.

The method by which I can harden any certain portions of a steel casting without hardening the remainder enables me to produce castings the surfaces of which to be machined or finished are soft and of the desired structure for finishing and machining, while those portions which lie immediately below or inwardly from the soft surfaces and which will form the surface when the soft portion is machined away are hardened, while still farther in toward the center of the casting the steel is soft. This is valuable in manufacturing cast-steel frogs, switches, wheels, disc, where it is desirable to have the major portion of the casting soft and have a finished or machined hardened wearing-surface deeper than it is now possible to give to steel castings, so far as I am aware.

As the invention is applicable to molds and castings of a great variety of shapes for different purposes, I do not wish to be understood as limiting myself to any particular shape or form or to any particular form or arrangement of tubes or receptacles for confining the hardening substance in the described position in the molds with relation to the castings to be formed therein. Any known substance which has the property when fused and incorporated with steel of rendering the steel hard and tough, and, if desired, in connection with receptacles of any suitable shape and material that will be readily fused by molten steel for holding the hardening substance in place in the molds, is regarded as coming within the scope of the invention.

What I claim as my invention is- 1. The method of forming a steel casting having a soft surface with a hardened portion lying inwardly from said surface, which consists in suspending hardening material within the cavity of the mold in such manner that the molten steel entering the mold may pass around it and between it and the confining wall or core adjacent to which said soft surface will lie, and then pouring molten steel into said mold thereby fusing the hardening substance with the steel and incorporating it in the casting. 2. The method of forming a steel casting with a soft surface and a hardened portion below the same in the body of the casting, which consists in suspending hardening material within the mold-cavity in such manner that the molten steel entering the mold may pass around it, and then pouring the molten steel into said mold-cavity thereby fusing the hardening substance with the steel and incorporating it in the casting.

3. The method of forming a steel casting with a soft surface and with a hardened portion lying below said surface, which consists in suspending hardening material within the mold-cavity a distance from the confiningwall adjacent to which said surface will lie, and then pouring the molten steel into said mold-cavity.

4. The method of forming steel castings with hardened portions, which consists in supporting a fusible case containing a hardening substance within the cavity of the mold in which the casting is to be made in such manner that the molten steel may pass around the casing and then pouring the molten steel into said mold, whereby the hardening substance and the casing are fused by and incorporated in the molten steel and the desired portions of the casting are made harder than the other portions.

5. The method of forming steel castings which consists in supporting a fusible metal casing containing pulverized or broken manganese within the mold-cavity in such mannerthat the molten steel may pass around the case and then pouring the molten steel into said mold-cavity, whereby the casing and the manganese are fused by and incorporated in the molten steel.

6. The method of making steel castings, which consists in supporting an aluminium case containing a hardening substance within the cavity of the mold and then pouring the molten steel into the mold, whereby the case and the hardening substance are fused with the molten steel.

7. The method of making steel castings, which consists in supporting an aluminium case containing pulverized or broken manganese within the cavity'of. the mold and then pouring the molten steel into the m0ld,wherebythe case and the manganese are fused with the molten steel.

8. Asteel casting having the surfaces thereof which are tobe machined or finished soft and of the desired structure for finishing and machining, and having those portionshard which lie immediately below or inwardly from the surfaces to be machined or finished.

9. Asteelcastinghavingthesurfacesthere-- of which are to be machined or finished soft and of the desired structure for finishing-and machining, and having those portions hard which lie immediately below or inwardlyfrom the surfaces to be machined or finished, while still farther in toward the centerof the casting the steel is soft.

10. The method of forming a steel casting havinga soft machineable surface and a relatively hard interior which consists-in suspending hardening material in the mold-cavity a distance from any of its confining walls 

